The Open Office suite is a freeware so it being shared on torrent websites is totally legal and not breaking any copyright laws. Microsoft requesting a DMCA takedown for Open Office download pages is therefore not justified, especially since they are not even the copyright owner in the first place. That said, it is likely that it was just an unfortunate accident and Google did not respond to the DMCA takedown notices by removing the pages. All are still up and Google clearly spotted the mistake which it does tend to do most of the time. Ultimately this incident is just another reason as to why there needs to be a more transparent and regulated DMCA takedown procedure to help weed out false, unjustified and incorrect DMCA takedown requests.